Seated occupant impact-injury minimizing method

ABSTRACT

A shock-load G-force minimizing seat structure and injury-minimizing methodology wherein the seat structure responds principally in non-springy compression, rather than in spring-loading bending, to vertically directed shock loads. The seat structure features an anti-springy frame structure which supports a thin and very lightweight seat cushion support spanner web formed preferably of a non-stretchy material, such as a material made out of elongate carbon-fiber strands.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division, and claims the priority filing date, ofapplication Ser. No. 10/426,103, filed Apr. 29, 2003 now U.S. Pat. No.6,789,844 for invention of Michael R. Dennis for “Seat Structure withAnti-Spring Spanner Element”. The entire contents of that applicationare hereby incorporated herein by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention pertains to seat structure, and in particular tomethodology associated with anti-spring, web spanner structure forsupporting an occupant-seating cushion in seat structure designed foruse in the setting of high-speed vehicle, such as an aircraft, tominimize injuries in hard and/or catastrophic impact events. The methodof the invention also pertains to the use of such seat structure whichfurther includes an anti-spring, compression-load seat-base structure.

Conventional seat design, insofar as it has been aimed at minimizinginjuries caused from a hard “bottoming-out” event, such as in a crashlanding in an aircraft, have typically introduced structuralarrangements which, unfortunately, and to some extent accidentally, tendto exacerbate the impact-injury problem. Such design often utilizes acollapsing or “stroking” behavior in an effort to minimize the totalload delivered to a seat occupant. This approach, however, frequentlyintroduces undesirable weight, complexity, and expense issues, and alsoadditionally enhances “springiness” in a seat structure—a situation thatcan actually lead to an amplification of damaging accelerations appliedto a seat occupant's spine. Increased springiness, counter-intuitive asthis may seem, introduces an enlarged rebound counter-accelerationfractions of a second after a dangerous impact occurs, and suchincreased counter-acceleration significantly contributes to serious, andoften fatal, injury.

The methodology of the present invention addresses this issue with aninnovative seat structure which, in use, is interposed a seat occupantand a vehicle frame, such as an aircraft frame, and which possessessubstantially no spring-loading and spring-back behavior. This seatstructure, disclosed in the environment of an aircraft, and in apreferred and best mode embodiment and manner of use which arespecifically illustrated and described herein, features a very thin,occupant-cushion-supporting spanner web formed of substantiallynon-stretchy and non-springy strand material, such as elongate carbonfiber, or Kevlar®, strand material, which is deployed under very modesttension between a pair of transverse, spaced, parallel, elongate andvery robust cylindrical tubes. These tubes are carried on an adjustable,selectively fore and aft repositionable, slider sub-frame which, inturn, rides slideably on a pair of spaced, lateral and parallelI-beam-like rails (seat-frame substructures) which are, effectively,directly anchored to the aircraft frame. The mechanism furnished forenabling selectable slide repositioning, and positional unlocking andlocking associated with this capability, do not form any part of thepresent invention, and are neither described nor illustrated herein.

These components of the seat frame—tubes, slider mechanism, rails andassociated structures—load principally in very modest-deflectioncompression, rather than in bending, and consequently make an importantcontribution to the non-spring-back performance of the entireseat-structure. The spanner web, non-stretchable as it is, offers anextremely light weight, thin-format direct cushion support structurewhich also specially exhibits substantially no spring-loading,spring-back response to loading activity, such as an impact-producedsharp, high-level accelerative loading.

These and other features and advantages which are offered by the presentinvention will become more fully evident and appreciated as thedescription that now follows is read in conjunction with theaccompanying drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 presents an isometric, side-frontal view of a preferred and bestmode embodiment of seat-structure constructed in accordance with theinvention. FIG. 1 includes a fragmentary illustration of an aircraft'sframe structure with respect to which this seat-structure is anchored.

FIG. 2 gives a larger-scale, top-plan view (with seat-back structureremoved) of what is shown in FIG. 1.

FIGS. 3–5, inclusive, each presents an even larger-scale, fragmentaryview (partially cross-sectional) of structural details taken along thelines 3—3, 4—4, and 5—5, respectively, shown in FIG. 2.

FIG. 6 presents three, story-telling, isometric views which describe, atleast in part, assembly of the cushion-supporting spanner structurewhich is employed in the seat structure of the present invention.

FIG. 7 is a simplified fragmentary detail illustrating one modified formof the invention.

FIG. 8 is a fragmentary cross section taken generally along the line 8—8in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings, and referring first of all to FIGS. 1–5,inclusive, shown generally at 10 is a preferred and best-modeanti-spring-back seat structure which is constructed for operation inaccordance with the present invention. Very specifically, thisillustrated seat-structure is constructed in accordance with a preferredand best mode embodiment of and manner of practicing the invention.Illustrated fragmentarily at 12 is structure that represents an aircraftframe with regard to which seat-structure, or seat, 10 is suitablerigidly anchored.

Seat 10 includes a non-springy, rigid frame 14, and mounted thereon, aswill be described, a thin, nominally flexible, substantiallyunstretchable spanner web 15 of material which is intended to support anappropriate, direct occupant-supporting cushion which is shown at 16 inFIG. 1. The design and construction of this cushion form no part of thepresent invention, but preferably, cushion 16 is made of a somewhat“soft” material which does not possess a springy nature.

Frame 14 includes lower and upper sub-frames 20, 22 respectively, whichare functionally united, in the region designated 24, for selectedfore-and-aft relative positional sliding and adjustment as isrepresented by double-ended arrow 26. The left and right lateral sidesof frame 14 (from an occupant's point of view) are shown at 14 a, 14 b(see particularly FIGS. 1 and 2), and the front and rear sides of thisframe are shown at 14 c, 14 d, respectively.

Lower sub-frame 20, also referred to herein as a mounting structure,includes two, elongate, laterally spaced, substantially parallel sidemembers 20 a, 20 b. These side members have a kind of I-beam-like crosssection, with different-width upper and lower flanges joined by acentral upright web, as shown. Members 20 a, 20 b are suitably anchoredto the aircraft frame.

Upper sub-frame 22 includes two, elongate, laterally spaced,substantially parallel side members 22 a, 22 b, each of which has thecross-sectional configuration clearly illustrated in FIG. 5. As can beseen, the lower portion of each of these side-members has a downwardlyfacing, somewhat C-shaped look. Projecting upwardly from this lowerportion is a substantially vertically disposed web which resides at thelaterally outer sides of members 22 a, 22 b. Members 22 a, 22 b areslideably mounted on members 20 a, 20 b, respectively, in lowersub-frame 20, with the C-shaped lower portions of members 22 a, 22 breceiving the upper flanges of members 20 a, 20 b, respectively.Low-friction-material shoes 28, made of a material such as ultra highmolecular weight polyethylene (UHMWPE), are interposed these fourlateral members (20 a, 20 b, 22 a, 22 b) as shown (see particularlyFIGS. 4 and 5).

As was mentioned earlier, an appropriate mechanism (not shown) isprovided for allowing a seat occupant selectively to adjust (in alockable and unlockable manner) the fore and aft positions of members 22a, 22 b on members of 20 a, 20 b.

Further included in upper sub-frame 22 are elongate, front and rear,transverse members 22 c, 22 d, respectively. These members, which arereferred to herein as web anchor members, each has a stout,cylindrical/tubular configuration, with a central strengthening webwhich is partially removed adjacent opposite ends to accommodate theinstallation of closure end caps, such as end cap 30 which is shown inFIG. 5. With specific reference to each end cap 30, each cap includes acentral, inwardly facing, hexagonal socket 30 a which, in a sliding-fitfashion, receives a hexagonal nut 32 that receives a mounting bolt 34which functions to anchor one end of the associated tubular member tothe upright web in a upper sub-frame lateral member (22 a, 22 b). Across-nut-and-bolt assembly 35 is employed to capture each end capwithin an end of one of the tubular members, with each hex nut 32 beinginitially freely received in a socket 30 a prior to assembly of eachtubular member with an end of one of members 22 a, 22 b. Collectively,members 22 a, 22 b, 22 c, 22 d define what is referred to herein as arectangular, personnel support span, or region, 36 (see particularlyFIGS. 2 and 3).

The several elongate components which make up the lower and uppersub-frames in seat-structure 10 exhibit substantially no springy bendingunder circumstances where a vertical load, such as an impact/shock load,is delivered between a seat occupant and the frame of the aircraft.Rather, these components respond to such a load primarily incompression. This is an important feature of the present invention.

Suitably anchored to members 22 c, 22 d, and substantially entirelyspanning previously mentioned rectangular region 36, is previouslymentioned spanner web 15. Referring to FIG. 6 along with FIGS. 1–5,inclusive, web 15 is effectively a two-layer structure, includingpreferably an inner layer 40 and a jacketing, outer layer 42. Innerlayer 40 is formed of a substantially non-stretchable strand material,such a Kevlar® fabric material, which includes plural, elongate strands40 a (see FIGS. 2, 5 and 6) that end up extending in a fore-and-aftdirection between upper sub-frame members 22 c, 22 d. Layer 40 ispreferably woven in nature, with cross fibres or strands having anorthogonal relationship. Outer jacketing layer 42 is formed preferablyof rip-stop Nylon®. FIG. 6 shows how spanner web 15 may be formed. Theseveral stages of construction are pictured in a quite self-explanatoryway from left-to-right in the three views which are presented in FIG. 6.Stitching 44 (FIGS. 2, 3 and 6) binds opposite ends of the effectivelycontinuous loop of the spanner web in final stages of construction. Thefinished “loop” has a somewhat “figure-8” (with a flattened, offsetcenter) configuration as viewed from a lateral side, or edge, of theloop. This configuration gives the spanner web a pair of opposite-end(front and rear) reverse loops 15 a, 15 b, respectively.

While this spanner web has been described in conjunction with formationfrom a Kevlar®-strand woven fabric material, it should be understoodthat other similar and suitable materials are and may become availablemade out of, for example, carbon-fiber material.

The completed spanner web is installed on sub-frame members 22 c, 22 das shown, with the installed web nominally possessing a certain modestamount of tension whereby it does not sag between these sub-framemembers.

FIGS. 7 and 8 illustrate a somewhat modified form of spanner-webconstruction and mounting. Here, such a modified web is shownfragmentarily at 46. With regard to this modified web, the modificationsexist at the two, opposite-end reverse bends which loop around uppersub-frame members 22 c, 22 d. Specifically, at these two locations, twoadditional web layers 48, 50 have been added so that they lieintermediate previously described outer layer 42 and members 22 c, 22 dwhen the web is mounted in place. Layer 48 is joined directly to layer42, and is formed of an appropriate load-spreading material, such asPoron® 90. Layer 50 is joined to layer 48, and is preferably formed ofan acceleration-rate-sensitive material, such as any one of the specificviscoelastic materials known as CF-42, CF-45, and CF-47.

Operational Description

With an occupant in seat 10, substantially the full weight of thatoccupant is borne by the spanner web. The web carries this load innon-stretching tension. From the spanner web, occupant load istransferred directly and dividedly to upper sub-frame 22 via front andrear tubular members 22 c, 22 d, respectively, which respond to suchload transfer, at least insofar as vertical load components areconcerned, in compression rather than in springy bending. From members22 c, 22 d, this divided occupant load is transferred in compression toupper sub-frame members 22 a, 22 b, through which members thistransferred load is delivered in compression through shoes 28, and lowersub-frame members 20 a, 22 b, in compression, to the aircraft frame.

In the event of a catastrophic or other vertically jolting occurrence,G-loads delivered to an occupant through seat 10 upon initial impactwill not cause any noticeable spring-back, vertical loading to occur inany portion of seat 10. Hence, there will not occur any springy reboundin the seat frame and spanner web structure, and in particular not anyrebound of the kind that we have learned is heavily responsible fordelivering extremely damaging, and even fatal, injuries to a seatoccupant. “Crash” tests performed with regard to the seat of thisinvention, with respect to “numbers” generated that relate to injurycausation, are remarkably low, and have proven to be, consistently andrepetitively, well below established “danger” thresholds. One importantkey to this remarkable behavior is the fact that, in sharp distinctionrelative to conventional seat structures, the seat structure of thisinvention does not introduce a damaging rebound response to impactevents.

Accordingly, a preferred embodiment and methodology of the presentinvention have been described and illustrated herein.Counter-intuitively, the structure and methodology of this inventionfurnish a seat support structure including spanner web structure which,by reducing almost to non-noticeablity any spring rebound action withrespect to a catastrophic vertical load imposed by a seat occupant onthe seat structure, damaging G-force transmission to that occupant issignificantly minimized. Those who are skilled in the art, after readingand reviewing the description and illustrations herein regarding thisinvention will appreciate that variations and modifications may be madewithout departing from the spirit of the invention.

1. A method of minimizing G-force impact injury to a person seated in avehicle which has a non-springy vehicle frame comprising creating anon-collapsing, non-vertical-motion person-seating structure whichexhibits substantially no vertical motion and no spring-loading-typerebound to a vertical compressive shock introduced to this structure,and following said creating, anchoring the created person-seatingstructure effectively directly to the vehicle frame.
 2. A method ofminimizing G-force impact injury to person seated in a vehicle which hasa non-springy vehicle frame comprising providing person-seating framestructure with a sub-frame whose structure responds toseated-occupant-introduced loads in compression and without anyappreciable flexing and bending, and which includes an open span adaptedto be spanned by a web of fabric material, spanning the sub-frame spanby anchoring such a web to the sub-frame, with the web being formed withelongate material strands that are non-stretchable, and utilizing theassembled combination of the sub-frame, the span and the spanning fabricweb to react to loads introduced thereto by a seated personsubstantially without any springy response.